Q&A
エラーとなっている <td><%= demo.getEra() %></td> の行を削除（コメントアウトではなく）して実行した場合、どうなりますか?
前提・実現したいこと
定義エラーをなくす。
発生している問題・エラーメッセージ
サーブレットでgetEra()というメソッドを定義したのにも関わらず、
org.apache.jasper.JasperException: JSPのクラスをコンパイルできません: JSPファイル: [/index.jsp] の中の[23]行目でエラーが発生しました The method getEra() is undefined for the type Demo 20:
と出てしまいます。
該当のソースコード
問題のコード（index.jsp）
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@page import="bean.Demo" %> <%@page import="java.util.List" %> <div class="p-3 mb-2 bg-dark text-white"> <% List<Demo> demos = (List<Demo>)request.getAttribute("demos"); %> <%@ include file="./layouts/header.html"%> <div class="container"> <h1>一覧</h1> <table class="table"> <tr> <th>ID</th> <th>名前</th> <th>年数</th> <th>元号</th> <th></th> </tr> <% for (Demo demo:demos) { %> <tr> <td><%= demo.getId() %></td> <td><%= demo.getName() %></td> <td><%= demo.getParticipant() %>年</td> <td><%= demo.getEra() %></td> <td> <a href="./Show?id=<%= demo.getId() %>" class="btn btn-sm btn-primary">詳細</a> </td> <td> <a href="./Edit?id=<%= demo.getId() %>" class="btn btn-sm btn-info">編集</a> </td> <td> <a href="./Delete?id=<%= demo.getId() %>" class="btn btn-sm btn-danger">削除</a> </td> </tr> <% } %> </table> <hr /> <a href="./new.jsp" class="btn btn-primary ">新規作成</a> </div> </div> <%@ include file="./layouts/footer.html"%>
メソッドを定義したソースコード(Demo.java)
package bean; public class Demo implements java.io.Serializable { private int id; private String name; private int participant; private String era; //getter public int getId() { return id; } public String getName() { return name; } public int getParticipant() { return participant; } public String getEra() { return era; } //setter public void setId(int id) { this.id = id; } public void setName(String name) { this.name = name; } public void setParticipant(int participant) { this.participant = participant; } public void setEra(String era) { this.era = era; } }
試したこと
メソッドを書き直したり、使用しているh2コンソールを変えたりしましたが、変わりませんでした。
###追記
発生してるエラー文です
org.apache.jasper.JasperException: JSPのクラスをコンパイルできません: JSPファイル: [/index.jsp] の中の[24]行目でエラーが発生しました The method getEra() is undefined for the type Demo 21: <%= demo.getId() %> 22: <%= demo.getName() %> 23: <%= demo.getParticipant() %>人 24: <%= demo.getEra() %> 25: 26: 詳細 27: Stacktrace: at org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:103) at org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:213) at org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:522) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:392) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:362) at org.apache.jasper.compiler.Compiler.compile(Compiler.java:346) at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:603) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:399) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329) at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:712) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:459) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:384) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312) at actions.Index.doGet(Index.java:42) at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at tool.EncodingFilter.doFilter(EncodingFilter.java:40) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:836) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1747) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.base/java.lang.Thread.run(Thread.java:835)
変数名を変えるとこのエラーが出てきます
org.h2.jdbc.JdbcSQLException: 列 "participant" が見つかりません Column "participant" not found [42122-197] at org.h2.message.DbException.getJdbcSQLException(DbException.java:357) at org.h2.message.DbException.get(DbException.java:179) at org.h2.message.DbException.get(DbException.java:155) at org.h2.jdbc.JdbcResultSet.getColumnIndex(JdbcResultSet.java:3148) at org.h2.jdbc.JdbcResultSet.get(JdbcResultSet.java:3247) at org.h2.jdbc.JdbcResultSet.getInt(JdbcResultSet.java:346) at org.apache.tomcat.dbcp.dbcp2.DelegatingResultSet.getInt(DelegatingResultSet.java:633) at org.apache.tomcat.dbcp.dbcp2.DelegatingResultSet.getInt(DelegatingResultSet.java:633) at dao.DemoDAO.index(DemoDAO.java:24) at actions.Index.doGet(Index.java:39) at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at tool.EncodingFilter.doFilter(EncodingFilter.java:40) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:836) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1747) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.base/java.lang.Thread.run(Thread.java:835)
問題の行を削除するとページはエラーなく表示されるのですが、
そこから他のページに飛ぶとページが白紙になってしまいます。
新規作成をすると、
org.h2.jdbc.JdbcSQLException: 列番号が一致しません Column count does not match; SQL statement: insert into demo values(null, ?, ?) [21002-197]
と出てしまいます。
自己解決
